<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
			// var str1=new String("aaabbbccc")
			// var str2="213123a"
			
			// console.log(str1.length)
			
			// String.prototype.getLength-function(){
			// 	alert(this.length)
			// }
			// var str=new String("abcdefg")
			// str.getLength()
			
			var str1=new String("abc123abc")
			var str2="你好！张三"
			console.log(str2.charAt(3))
			
			console.log(str1.indexOf("123"))
			console.log(str1.indexOf("abc",3))
			console.log(str1.indexOf("abc"))
			
			var str3="abcdefghijk"
			console.log(str1.slice(3,7))
			console.log(str1.substr(3,4))
			console.log(str1.lastIndexOf(3,7))
			
			var str4="dawdacawfwafa"
			console.log(str4.toLowerCase())
			console.log(str4.toUpperCase())
			
			var str5="aaa"
			var str6="bbb"
			var str7="vvv"
			console.log(str5.concat(str6,str7))
			
			var str8="aa,bb,cc"
			var strArr=str8.split(",")
			console.log(strArr)
			
			
		</script>
		
	</body>
</html>
